Method of preparing an optical security component having a metallic appearance, and component thus produced

Abstract

A method of preparing an optical security component having a metallic appearance and having a diffraction grating. The method includes the following steps: preparing a transparent polyester film; depositing a stamping layer, into which the hologram producer has pressed the appropriate microstructures; stamping; vacuum depositing a fine layer of a dielectric material having a high optical index; coating or printing at least one layer of translucent coloured varnish; and vacuum depositing a layer of aluminium. An optical security component thus produced is also disclosed.

1 . Process for the preparation of an optical security component having a metallized appearance, and comprising a diffraction network, characterized in that it comprises a step of preparation of a transparent polyester film, a step of deposition of a stamping layer in which the hologram producer will press the appropriate microstructures, a step of stamping and a step of deposition under vacuum of a thin layer of a dielectric material of high optical index, followed by a step of coating or printing at least one layer of colored translucent varnish and a step of deposition under vacuum of an aluminum layer.  
   
   
       2 . Process for the preparation of an optical security component having a metallized appearance according to  claim 1 , characterized in that the layer of a dielectric material of high optical index is constituted by zinc sulfide ZnS of a thickness of about 60 nm.  
   
   
       3 . Process for the preparation of an optical security component having a metallized appearance according to  claim 1 , characterized in that the layer of translucent varnish has a thickness of about 55 nm.  
   
   
       4 . Process for the preparation of an optical security component having a metallized appearance according to  claim 1 , characterized in that it comprises a step of superposition on the transparent film  1  of a detachment layer.  
   
   
       5 . Process for the preparation of an optical security component having a metallized appearance according to  claim 1 , characterized in that it comprises a supplemental step of partial demetallization of the aluminum layer.  
   
   
       6 . Process for the preparation of an optical security component having a metallized appearance according to  claim 1 , characterized in that a plurality of layers of colored varnish are imprinted.  
   
   
       7 . Optical security component having a metallized appearance, and comprising a diffraction network characterized in that it is constituted by a transparent polyester film  1 , a stamping layer  3 , a layer  7  of high optical index of refraction, a thin layer  4   b  is of a colored varnish, preferably translucent, and a layer of aluminum.  
   
   
       8 . Optical security component according to  claim 7 , characterized in that it comprises moreover a detachment layer  2 .  
   
   
       9 . Optical security component according to  claim 7 , characterized in that it comprises moreover a layer  4   b  is of translucent colored varnish imprinted locally in registry or not with the hologram.  
   
   
       10 . Optical security component according to  claim 9 , characterized in that it comprises moreover a transparent layer which carries a level 2 security of the UV or infrared type.  
   
   
       11 . Optical security component according to  claim 8 , characterized in that it comprises moreover a detachment layer  2 .